Spray Coating Control Device

ABSTRACT

The invention relates to an electronic spraycoating control device implementing spraycoating methods and containing at least one manually driven program selecting element to select programs from two different groups of programs, further containing a plurality of manually driven parameter setting elements and display units to automatically display the adjusted parameter references values.

The present invention relates to an electronic spraycoating controldevice with which to implement spraycoating procedures as claimed in thepreamble of claim 1.

The control device controls spray units which spray coating materialsonto objects to be coated. The coating material may be a liquid, forinstance a paint or the like, or preferably a coating powder. Thecoating material is sprayed on an object to be coated and then ispermanently bonded to it by heating it. There are spray units with orwithout high voltage electrodes to electrostatically charge the coatingmaterial. Furthermore there are tribo-electric spray units for coatingpowders wherein the coating powder is charged by its friction against aduct wall. The spray units may be manually operated (manual guns) orthey may rest on a support (automated guns). They are also called manualguns in the first above case and automated guns in the second one evenwhen they are not gun-shaped but for instance are tubular or in the formof a block fitted with several nozzle apertures.

STATE OF THE ART

U.S. Pat. No. 4,324,361 shows an electrostatic spray unit to spraycoating powder onto objects. The unit comprises high voltage electrodesto electrostatically charge the coating material, an air duct forcompressed air enhancing coating powder atomization, and a pressurizedduct to produce an air envelope around the atomized powder cloud. Theair envelope also may be used to impart a specific shape to the powdercloud. In the later case this kind of pressurized air is also called“shaping air”. U.S. Pat. No. 4,289,278 shows an electrostatic powderspraycoating device fitted with an electrode in a compressed air duct.U.S. Pat. No. 4,090,666 discloses a spray unit wherein the coatingpowder is charged tribo-electrically. U.S. Pat. No. 4,941,778 shows aspraycoating unit with an electronic control. U.S. Pat. No. 4,357,900discloses spraycoating equipment comprising several spray units in theform of automated guns and with several electronic controls. TheEuropean patent documents EP 0 706 102 B1 and 0 899 018 B1 show asuperposed control to which are hooked up several control implementseach of which is connected to at least one spray unit.

Heretofore different control devices have been conventionally used forautomated spray units (automated guns) and for manual spray units(manual guns). However the control implements for automated spray unitsalso may be used for manual spray units. But both coating quality andefficiency are very much affected by operator experience as regardsmanual spray units. Therefore, unlike the control devices for automatedspray units, the manual spray unit control devices contain spraycoatingprograms not only having variable parameters, but also having fixedparameters. The said fixed parameters are those especially critical forcoating quality and/or efficiency and requiring much experience whensetting parameter values, for instance the voltage of high voltageelectrodes used in electro-statically charging the coating material, andpreferably also the electrode current. The fixed parameters are set atvalues that were empirically found to be especially advantageous. Such afeature however entails the drawback that the customer needs at leasttwo different control devices.

The objective of the present invention is to offer an engineeringsolution whereby customer operation of spraycoating shall be simpler andmore economical while retaining good coating quality and high coatingefficiency.

This problem is solved by the features of claim 1 of the presentinvention.

Further features of the invention are defined in the dependent claims.

The invention is elucidated below in relation to the drawings and forpreferred, illustrative implementations.

FIG. 1 is a schematic front view of an electronic spraycoating controldevice of the invention to implement spraycoating methods,

FIG. 2 schematically shows a spraycoating unit fitted with a controldevice of the invention, and

FIG. 3 schematically shows a spraycoating facility fitted with at leastone control device of the invention.

To implement spraycoating methods, the spraycoating control device 2 ofthe invention shown in FIG. 1 contains a plurality of programs from afirst group of programs each containing several adjustable parameters;further manually driven parameter setting elements 4, 6, 8, 10, 12, 14,16 and 18 to set parameter reference values; and optical parameterdisplay units 20, 22, 24, 26 to automatically display the set parameterreference values and the actual parameter values.

Preferably the parameter setting elements 4 through 18 and the displayunits 20 through 26 are situated all in the same operational pane 28 ofthe control device 2.

Preferably notations or symbols of the parameters are situated in theoperating pane 28, for instance in the form of a cloud symbol 32 for therate of coating powder fed to a spray unit (spray gun); a symbol 34, foran object in a flow of air, as the notation for the total quantity ofair, where coating powder is automatically fed to a spray unit; a symbol36 in the form of the letters μA for the electrode spray current fromone or more high voltage electrodes of the spray unit; a symbol 38 inthe form of the letters kV for the voltage at the minimum of one highvoltage electrode; a symbol 40 having one or several upward-pointingarrows on a cross bar for the rate of fluidizing compressed air flowinginto a container to loosen coating powder therein or to fluidize it; anda symbol 42, in the form of an arrow within a rectangle, for electroderinsing air to rinse the high voltage electrode with compressed air.Obviously other or additional parameters may be provided, for instancecompressed shaping air to shape the coating cloud sprayed by the sprayunit.

Preferably the parameter setting elements are keys, preferablymechanical, pressure-responsive keys. In other embodiment modes, saidkeys also may be capacitive or inductive or touch-sensitive keys. Theembodiment mode of FIG. 1 comprises two such key-like setting elements4,6; 8,10; 12,14; 16,18 for each parameter, in every case one settingelement being denoted by a minus sign and the other by a plus sign.Actuating the plus sign setting element raises the particular parametervalue and actuating the minus sign setting element lowers it. One of thedisplay units 20, 22, 24 or 26 is associated with the minus and plussigns of the same parameter. Preferably said display units are luminous,preferably multi-segment luminous displays.

FIG. 1 shows that not only one, but two symbols 36 and 40 representingtwo parameters are allocated to the display unit 24 and to the tworelated setting elements (keys) 12 and 14. In similar manner, not onlyone, but two symbols 38 and 42 are allocated for two parameters to thedisplay unit 26 and to the related two setting elements (plus and minuskeys) 16, 18. At each of the two display units 24 and 26, the particularparameter of the second symbol 40 resp. 42 is stored in another memoryplane than the parameter of the other symbols 32, 34, 36, 38. A toggleswitch, preferably a key 44, allows particular reversals between thesaid planes in order to activate the particular parameters of eitherplane.

The control device 2 of the invention comprises, in addition to theprograms of the first group of programs (not shown), also at least one,preferably several and illustratively three programs of a second groupof programs (not shown) of which at least one program comprises anadjustable parameter and a fixed parameter. Moreover the inventioncomprises at least one program selecting element to alternatively switchON either one program from the first group of programs or from thesecond group of programs. In the illustrative embodiment mode of FIG. 1,there are one program selecting element acting as the program groupselecting element 46 to activate the first group of programs and threeprogram selecting elements 48, 50 and 52 to activate each a particularprogram of the second group of programs, preferably in the form of keys46, 48, 50, 52. The keys 46, 48, 50, 52 selecting a set of groups andselecting a program preferably are mechanical, pressure-responsive keys.However capacitive or inductive keys and soft-touch sensors also may beused. The first group of programs is selected by manually pushing theprogram group selecting element 46. A plus key 54 and a minus key 56 areassociated as program switching elements to said program group selectingelement. Every time the plus program switching key 54 is pushed, anotherprogram group is activated in a predetermined, ascending sequence, andevery time the other program switching key 56 is pushed, another programfrom the first group of programs is activated in the reverse, descendingorder. The particular program being activated is displayed in an opticalprogram display unit 58, for instance in the form of a program numeral.Preferably the program display unit 58 is a luminous display, preferablya seven segment luminous display.

The program selecting elements 46, 48, 50 and 52 in the form of keys areconfigured preferably in a rectangular array, preferably on edge, in themanner of a rhombus. The program group selecting lament 46 is configuredin the upper corner and its associated two plus and minus keys 54 and 56are mounted right and left of it. The program display unit 58 issituated above said keys 54 and 56. Illustratively the program groupselecting element 46 selecting the first group of programs is denoted bythe symbol “P”. The program selecting elements each selecting aparticular program of the second group of programs are denoted bysymbols indicating the kind of spraycoating intended by their selectedprograms. Illustratively the program selecting element 48 is shown witha cloud and a vertical bar denoting a coating program suitable forpriming or a basic coating. The symbol of the second program selectingelement 50 is for a program appropriate for complexly shaped objects,for instance for multi-stepped objects. And the third program selectingelement 52 of the second group is denoted by two vertical linesindicating a program that implements further, or top, coatings. Thesethree program selecting elements 48, 50, 52 of the second group ofprograms also contain the symbol of a spraycoating powder cloud.

Once the first group of programs has been selected by pushing theprogram group selecting elements 46, the values of all parameters 32,34, 36, 38, 40 and 42 can be set. Once a parameter value has been set,the parameter display units 20, 22, 24 and 26 each indicate theparameter reference value. In a preferred embodiment of the presentinvention, the control device 2 is designed in a manner that a givenparameter's actual value, instead of the reference value, is indicatedafter a given time interval.

Pushing one of the program selecting elements 48, 50, 52, a programassociated with the particular program selecting element is selectedthat illustratively contains the adjustable parameters 32, 34 as thosethat shall be set, and additionally contains at least one furtherparameter, for instance the parameters 36 and 38 in the form of highvoltage and the current at this voltage as the fixed parameter. In otherwords, these two fixed parameters 36 and 38 from the second programgroup are adjustable parameters in the first group of parameters.

The parameters of the first group of programs and those of the secondgroup of programs indeed are the same and they also may be set at theparameter setting elements 4, 6, 8, 10, 12, 14, 16, 18 and be indicatedas well at the same parameter display units 20, 22, 24 and 26, howeverthey may be at different values because the parameter values of thefirst group of programs are stored at different memory sites than theparameter values of the second group of programs.

Preferably the operations panel 28 consists of a single-layer ormulti-layer planar structure. The selecting and setting elements as wellas the display units preferably are integrated into the planar structureof the control panel 28. This control and display panel 28 issub-divided into a programming area 60 and a parameter area 62 which canbe distinguished visually. The parameter area 62 is situated above theprogramming area 60. The switching key 44 is positioned between said twoareas 60 and 62. All the program selecting elements 46, 48, 50, 52, 54,56 and the program display unit 58 are configured in the programmingarea 60. The programming area 60 may be extended laterally to furtherinclude an ON-switching element 64 and an OFF-switching element 66, thatpreferably shall also be keys, preferably also a special key 68 forspecial function. The parameter display units 20, 22, 24 and 26, furtherthe parameter setting elements 4, 6, 8, 10, 12, 14, 16, 18 and theparameter symbols 32, 34, 36, 38, 40, 42 are situated in the parameterarea 62. Preferably the parameter area 62 in turn is sub-divided intofour sub-areas two of which are superposed one above the other and twoof which are laterally adjoining. As a result the operating elements andthe display units can be serviced easily and ergonomically.

The control device is fitted with an electric power terminal 70, and acompressed air intake 72, to receive electric power and compressed airrespectively. This control device furthermore is fitted with at leastone power output 74 and at least two or for instance three or fourcompressed air outlets 76, 77, 78, 79 80 to apply compressed air inregulated manner.

FIG. 2 schematically shows the control device of FIG. 1 being connectedto a spray unit 82, an injector 84 and a powder container 86. Compressedair from the compressed air outlet 76 of the control device 2 serves asconveying air which, inside the injector 84, aspirates coating powderout of the powder container and feeds it through the powder line 88 tothe spray unit 82. Within the injector 84, compressed air from thecompressed air outlet 77 of the control device 2 is fed to the flow ofpowder and conveying air to enhance powder conveyance to the spray unit82. Compressed air from the compressed air outlet 78 of the controldevice 2 flows through a perforated container base 87 and loosens orfluidizes the powder in the power container 86. Compressed air from thecompressed air outlet 79 of the control device 2 illustratively is usedto rinse the electrodes in the spray unit 82. Compressed air at thecompressed air outlet 80 of the control device 2 illustratively servesas shaping air for the coating powder sprayed by the spray unit 82.

As shown in FIG. 3, the control device 2 not only may control the sprayunit 82, but also a positioning means 90 for instance an adjustablestand or a robot supporting the spray unit 82 and able to point it indifferent directions relative to an object 92 within a spraycoatingcabin 94. Several control devices 2 of the invention also may be mountedto an overhead control unit to control several spray units 82 as afunction of the kind and the particular transport position of theobjects 92 to be coated relative to the spraycoating cabin 94. FIG. 3schematically shows a transportation system 96 moving the objects 92 tobe coated through the spraycoating cabin in the direction 98. Thespraycoating cabin 94 may be fitted with an object recognizing sensor100. The objects 92 to be coated may be fitted with an identifying tag102.

1. An electronic spraycoating control device implementing a spraycoatingmethod and containing: a plurality-of programs from a first group ofprograms each containing several adjustable parameters; manually drivenparameter setting elements to set parameter reference values for theadjustable parameters; optical display units to automatically displaythe set parameter reference values, characterized by: at least oneprogram, from a second group of programs, that comprises at least oneadjust able parameter and at least one fixed parameter; at least onemanually driven program selecting element to alternatively switching ONeach time either one of the programs from the first group of programs orof the second group of programs.
 2. Control device as claimed in claim1, characterized in that the minimum of one adjustable parameter of thesecond group of programs also is an adjustable parameter from the firstgroup of programs; in that the minimum of one fixed parameter from thesecond group of programs is an adjustable parameter from the first groupof parameters; in that storage sites are provided wherein the parameterreference values of the first group of pro grams and the parameterreference values of the second group of programs may be stored in memoryindependently of one another; that the adjustable parameter referencevalues of the second group of programs can be set at the same parametersetting elements of the particular parameters as the adjustableparameter reference values of the first group of programs and can bedisplayed at the same related display units of the particular parametersas the parameter reference values of the adjustable parameters of thefirst group of programs, and that at least one of the two parametervalues, namely reference value or actual value of the fixed parameter,can be displayed at the display unit of the same variable parameter ofthe first group of programs whenever when a program from the secondgroup of programs was selected at the minimum of one program selectingelement instead of a program form the first group of programs. 3.Control device as claimed in 1, characterized in that it comprises aprogram-group selecting-element which is selected as a program selectingelement to select the first group of programs instead of the secondgroup of programs and in that two program switching elements areconfigured near this program group selecting element, each actuation ofone of these program switching elements driving another pro gram fromthe first group of programs and with each actuation of the other programswitching element driving another program from the first group ofprograms in the reverse sequence, and in that said control unit alsocomprises an optical display to show the particular activated programfrom the first group of programs.
 4. Control device as claimed in claim1, characterized in that each program of the second group of programs isfitted with its own program selecting element which when manually drivenactivates the particular program from the second group of programsregardless of another program from the second group of programs or aprogram from the first group of programs having been activated beforesaid drive action, activation of one program automatically deactivatingall other programs.
 5. Control device as claimed in claim 1,characterized in that the minimum of one program selecting element ineach case shall be a mechanical, pressure-responsive key.
 6. Controldevice as claimed in claim 1, characterized in that the parametersetting keys are mechanical, pressure-responsive keys.
 7. Control deviceas claimed in claim 1, characterized by optically recognizable parametersymbols configured at or adjacent to the parameter setting elements andsymbolizing the nature of the parameters, preferably by means ofself-luminous or illuminated parameter symbols.
 8. Control device asclaimed in claim 1, characterized in that the parameters are stored indifferent, alternatively activated planes.
 9. Control device as claimedin claim 1, characterized in that the display units are luminousdisplays, preferably multi-segment light displays.
 10. Control device asclaimed in claim 1, characterized in that the parameter settingelements, the display units and the minimum of one program selectingelement are configured in one operating pane and preferably areintegrated in a planar structure.
 11. Control device as claimed in claim10, characterized in that the operating pane is sub-divided into aprogram area and a parameter area in optically recognizable manner, theparameter area being configured above the program area, in that theminimum of one program selecting element is configured in the programarea, and in that all parameter setting elements are configured in theparameter area.
 12. Control device as claimed in claim 1, characterizedin that the display units are designed in a manner that upon a parameteractivation they will first automatically display its reference value andthen, after a predetermined time interval, they will automaticallyswitch to displaying said parameter's actual value.